Staedtler Scale Ruler is perfect if you're doing technical drawings or other work where you need to measure and create using ratios | An inexpensive quality scale ruler | Durable plastic construction with long-lasting graduations | Ideal for students | Tough, flexible, climatically stable and will not discolour or become brittle with age | It provides a 1:1 and 1:2 ratio on the front and a 1:5 and 1:10 ratio on the back | Ideal for students